Principle #2: Ice is the dominant feature of the Polar Regions.
2A: Ice is dynamic and comes in many shapes and sizes—big, small, floating in water or layered on land, thin or thick, solid or porous soft.
- 2A-1: Land ice includes glaciers and ice sheets made from compacted snow (freshwater). Glaciers and ice sheets can extend over the ocean. Ice sheets that extend over the ocean are called ice shelves.
- 2A-2: Glaciers can break off (calve) into chunks that fall into the ocean as icebergs and cause sea level to rise.
- 2A-3: Icebergs are made of freshwater and float in the ocean. Icebergs move with winds and ocean currents.
- 2A-4: Sea ice forms when sea water freezes. The resulting ice is made from mostly fresh water because the salt precipitates out during the freezing process.
2B: Ice shapes the Polar landscape.
- 2B-1: Tundra is a treeless area with permanently frozen soil (permafrost) and low growing vegetation.
- 2B-2: Ice sheets and continental glaciers (land ice) are not static. Due to gravity, they flow downhill at varying rates of speed. Moving ice can move rocks and erode soil in its path.
- 2B-3: Areas of land ice larger than 50km2 are found only on Greenland and Antarctica. The Antarctic ice sheets are the largest on Earth, containing 90% of the world’s ice, while the Greenland ice sheet contains 10%.
- 2B-4: It is estimated that all the world’s ice caps, glaciers and permanent snow contain 68.7% of the freshwater available on Earth. Freshwater is only 1.74% of the total amount of water on Earth. “Unlocking” freshwater from ice caps and glaciers will have ripple effects on the global ecosystem.
2C: Sea ice naturally shrinks and expands with the seasons. However, this natural dynamic cycle is affected by increasing air and water temperatures occurring at the Poles due to climate change.